Muffler



Jan. 3, 1961 R. B. SMITH ElAL 2,965,955 v MUFFLER Filed Aug. 1'5. 1958 ka" "VA ROY B. SMlT VERNON N. HO ERMAN ATTORNEY Patented .lan. 3,l$filice 2 6 5 MUFFLER Roy Smith, Rte. 5. Washington C.H.., Ohio, and VernonN. nolderman, 6180 OlentangyBlvd Columbus, Ohio Filed Aug. 13, 1958,Ser. N0. 754,893

2 Claims. (Cl. 181- 53) invention disclosed and claimed in thisapplication relates to devices for dampening pulsation and for :coolingheated gases. Such devices include ifO-Y example, mothers and exhaustsilencers for combustion engines and particularly for automotiveengines. Manyattemptsihave been made to produce an exhaust mufiier which'will eliminate the noise of exhaust gases and which will cause butlittle back pressure on the motor. Most of these attempts have beenbased upon the gradual expansion principle according to which exhaustgases are allowed to expand gradually before they are exhausted in theatmosphere to reduce their'temperature and pressure, or upon theprinciple of attempting to break up-or sub-divide the stream of gases inorder to reduce the noise of the exhaust.

The mutilers disclosed in'this application as embodiments of ourinvention are generally mufflers of the subdivision type but employ bothof-the above principles in cooling and dampening and are designedexpressly for use on present day multi-cylinder engines ot the internalcombustion type using diesel oil, gasoline, or propane as a fuel. Manyof the prior art mufflers of the subdivision type were built upon theprinciple of providing bafiles within the mufller which oppose passageof gases immediately on entering the mufiler. About 1946 the largesttruck engine in corrunon use had a 416 cubic inch displacement with atop speed of 2100 rpm. and a compression ratio of 6 to 1. The commonexhaust pipe size at that time was less than three inches diameter(usually about 2 /2 inches), but in 1958 "We have truck engines having535 cubic inch displacements operating at 3960 rpm. with a compressionratio of 8 to l and devcloping around 250 hp. in 1945 the gasoline usedwas formed with a tetraethyl lead additive which encouraged slowburning. Today we add boron compounds to the fuel which encourages rapidburning and resists pre-ignition by compression heat. This new gas isextra hot. The new engines are fast with high compression ratios, anddischarge gases extremely rapidly so that pressure puffs are created andwill remain separated until. they are cooled and compressed or areotherwise smoothed out. The exhaust pipe sizes range from 3 to 4- incheswhich expeditcs the how of gas from the engine, but puts more burdenupon the mufilers. Present day rnuftiers of prior art designs areinadequate to handle this extreme heat because they employ bafiles andthey take the first impact at one spot on the first baffle and ordinarymetals employed in .the bafiles will not withstand all of the heatimposed upon them, especially where these baflles are confinedwithin theinterior of the mufiler and are not subject to cooling air flowing overthem. After the first balfie is burned out the second it attacked, etc.Internal parts in present day rmiillers burn up completely in a Veryshort time. So the problem today is not only reduction of noise but moreimportantly the reduction of heat.

One of the objects of our invention is the provision'of a new andimproved pulsation dampener or heat reducer of the type of mothers orsilencers for multi-cylinder engines of the combustion type today usedon heavy duty trucks.

A further object of our invention is the provision of a muffier of thetype above described which is extremely resistant to the high heatproduced under present day conditions. A

This is accomplished largely by gradually reducing pres sure andconsequently velocity by drawing olT portions of the hot gases through aplurality of tubes interconnecting the inlet and outlet chambers of themuffler. These tubes are so situated and graduated that theyprogressively reduce i e pressure and velocity. This also results in thereduction of heat inasmuch as the outsides of the inlet and outletchambers and of the interconnecting tubes are always exposed to coolingair. The shape of the outside of the mufiier encourages rapid cooling.

A further obiect of our invention is the provision of such a mufflerthat may be manufactured at a relatively low cost.

A further object o-f our invention is the provision of a muffler whichdirects the gases through a plurality of predetermined 3-shaped pathsand step by step positively smooths out the pressure putts produced bythe internal combustion engine.

A further object of our invention is to provide a muffier With inlet andoutlet chambers or conduits which are tapered or graduated so that thearea is substantially prop'ortionate to the area of the tubes orinterconnecting conduits available at that point in the chambers.

A further object of our invention is the provision of a muffler in whichevery part exposed to heat is also exposed to cooling air thus reducingtemperatures rapidly.

A further object or" our invention is to provide a mu tfler of smallsize, light weight, and economical to manufacture which is ettective toremove and cool the exhaust gases and to silence the exhaust noisesWithin a reasonable time.

A further object of our invention is to provide a muffier Which isuniversal in the sense that it is usable with engines of various sizesand having various sized exhaust pipes.

A further object of our invention is to provide a mufller which avoidsthe use of any bathing of any kind within the interior of the mufflerespecially bafiiing which absorbs the first impact of the hot gases.

A further object is to provide a mutiler which slows the velocity of thehot gases and cools them.

A further object of our invention is to provide a muffier in which theinlet is located in a part of the-muffler higher than the outlet toavoid trapping of condensation and thus to avoid excessive rust-out ofthe muffler.

Further objects and features of our invention will be apparent from thefollowing specification and claims when considered in connection withthe accompanying drawings.

in the drawings we have shown two embodiments of our invention.

In the drawings:

Fig. 1 is a view in side elevation of one embodiment of our invention;

Fig. 2 is a view in side eleva ion of a different embodiment of ourinvention;

Fig. 3 is a view in end elevation taken from substantially along theline 33 of Fig. 2 showing the embodiment of our invention disclosed inFig. 2; and

Fig. 4 is a view in side elevation of a sheet metal stamping used informing the muffler of the embodiment of our invention shown in Figs. 2and 3.

No available present day mufl'iers can stand the high heat of presentday motors used on large trucks for any extended time. Running at fullpower a 500 cubic inch engine runs with the exhaust manifold and theexhaust pipe cherry red (i.e. approximately 1200 :2). One truck in usetoday has an exhaust which measures 1700" F. at the exhaust pipe. it isthus necessary that both the pressure and the temperature be reducedwithout the use of bafiies or other obstructions as such bafiles andother obstructions burn out usually in two or three weeks time on asteady truck haul. Muffiers constructed according to our invention havebeen tested on the dynamomcter and have stood such tests with 500 cubicinch engines and have resisted burning up tendency in the same manner asthe exhaust pipes do. Our mufflers are basically re turn tube mufflersforcing the gases into an 8 flow in which the flow of gases is firstseparated and then united. Cross passages are provided at each end ofthe muffler which prevent gathering of condensation.

Referring now to the drawings for a detailed description of theembodiments of our invention shown, it may be seen that we have shown inFig. 1 a muffier comprising an inlet tube, chamber, or conduit 11, anoutlet tube, chamber, or conduit 12, and sloping interconnectingconduits or tubes 13, 14, 15, 16 and 17. These interconnecting conduitsor tubes 13-17 inclusive slope downward toward the inlet end of themufiler. They are welded to the inlet conduit 11 and the outlet conduit12 so that their end openings register with openings formed in the inletand outlet conduits. It is to be noted that the tubes toward the right(e.g. tube 17) are smaller in diameter than the tubes adjacent the left(e.g. 13). Cooling air passes over these tubes so that in spite of thehigh heat of the gases therein they withstand the heat and are veryeffective in cooling and contracting the hot gases. In addition to thesloping conduits 13 to 17 inclusive, we provide perpendicular tubes orconduits 21 and 22, the former being provided at the front or inlet endof the muffler and the latter provided near the outlet end thereof.These perpendicular conduits serve partly for the transmission andcooling of hot gases from the inlet conduit to the outlet conduit, butalso serve to insure that condensation products shall drain from theupper inlet conduit to the lower outlet conduit. The inlet conduit 11has a relatively large inlet opening 23 and the outlet con duit 12 has arelatively large outlet opening 24 which however is smaller than theinlet opening 23.

In Fig. 2 we have shown another embodiment of our invention in whichinstead of having separated inlet and outlet tubes joined byinterconnecting tubes welded thereto, we form our improved muffler totwo complementary shells clamped or secured together in any convenientmanner. As shown, the embodiment in Fig. 2 has two shells with flangeswhich are crimped to each other by such flanges and also secured to eachother by clamps around the necks of the inlet and outlet ends of theconduits. However, any convenient manner of securing the two shellstogether would be satisfactory. This embodiment comprises a mufller 31having a pair of shells such as the shell 32 shown in Fig. 2 and Fig. 3,and such as the shell 33 shown in Figs. 3 and 4.

The two shells cooperate to form an upper inlet conduit 44 and a loweroutlet conduit 45. it may be seen that the inlet conduit 44 tapers froma relatively large inlet opening 46 to a smaller opposite portion 47which is closed as at 48. The outlet conduit 45 tapers from a relativelysmall closed end 51 to a relatively large outlet opening 52. Connectingthe inlet conduit with the outlet conduit are a plurality ofinterconnecting conduits formed by grooves in each of the castings. Theoutline of these interconnecting conduits is shown in Fig. 2 at 53, 54,55, 56 and 57. The conduits 5357 inclusive, are all sloping downward tothe left and respectively connect and lead from the smaller portion ofthe inlet conduit 44 toward the smaller portion of the outlet conduit45. In addition to the sloping conduits 53-57 inclusive, we also provideadjacent the ends of the inlet and outlet conduits smaller perpendicularconduits 58 and 59 which also serve to aid in the function of passingthe heated gases from the inlet conduit 44 to the outlet conduit 45 andthus supplement the conduits 53-57 inclusive, in this respect, but alsoare primarily constructed for the purpose of insuring that condensationshall be conveyed from the inlet conduit 44 to the outlet conduit 45 andthence driven out with the passage of exhaust gases. The provision oftubes 13 to 17 and 5357 gives a longer path for the gases in a givendimension and thus aids in cooling. The S-shaped path also slows downthe passage of the gases.

In Fig. 4 we have shown the construction of one of the shells (i.e. 33)which together with the complementary shell forms the mufller 31. It maybe seen that this shell 33 is provided with grooves 63 to 67 inclusive,which cooperate with similar grooves in the complementary shell section32 to form the conduits 53 to 57 inclusive, respectively. It is alsoprovided with grooves 68 and 69 which cooperate with correspondinggrooves in the complementary shell 32 to form the conduits 58 and 59respectively.

As shown in Figs. 2 and 4 we provide flanges 71, 72, 73 and 74 on thestamping 33. These flanges cooperate with similar flanges on thecomplementary stamping 32 and are crimped in the manner shown at 75 and76 to secure the two stampings to each other and thus form the integralmuffler. Clamps 77 and 73 secured around the necks of the inlet 46 andthe outlet 52 also aid in securing the two stampings to each other.

We prefer that the total area of the tubes 13 to 17 inclusive (or thetubes 53-57 inclusive) shall at least equal the total area of the inletport 23 (or the inlet port 46) of the inlet conduits or chambers. Thuswe use a large number of small diameter tubes. We prefer as shown inFig.1 that the connecting tubes nearer to the inlet end shall be largerin diameter than the connecting tubes at or near the outlet end.However, in the interests of economy and simplicity at times we usetubes of the same diameter from front to rear of the muflier, and attimes for the same reasons, we also use less area in the connectingtubes than at the inlet relying on the reduction of volume of the gasesas they cool to reduce back pressure. Thus in one muffler constructedaccording to our invention, we used 25 connecting tubes each having aninternal diameter of W of an inch with a manifold having an inlet portin the inlet chamber having a four-inch internal diameter. This mufflerweighed twelve and onehalf pounds and was 22 inches long. It reduced thenoise of the engine to the acceptable range and was within theacceptable range of back pressure. it took the place of a mufflerweighing 37 pounds, which was 42 inches long and 9 inches in diameter.It operated with equal or better efficiency. We prefer that an adapterbe used at the outlet of our mufiler which will further contract thegases into a smooth stream.

We prefer to have enough interconnecting tubes and/ or tubes having arelatively large internal diameter relative to the internal diameter ofthe inlet port of the inlet chamber so that the area of theinterconnecting tubes at least equals the area of the inlet port. Thus,for an inlet chamber having an internal diameter of four inches, weprefer to use about 25 connecting tubes having from to /5 inchesinternal diameter. We prefer for mufiiers having about 3 inch internaldiameter at the inlet port of the inlet chamber to use about 25connecting tubes each having internal diameter of about W Of course, inthe drawings we have shown only five or six connecting tubes. This isfor the reason that the showing of a larger number would unnecessarilycomplicate the drawings. It is to be understood, however, that the areaof the cross-section of the connecting tubes equals, or is greater than,the area of the cross-section of the inlet port.

It is to be understood that the above described embodiments of ourinvention are for the purpose of illustration only and various changesmay be made therein without departing from the spirit and scope of thein vention.

We claim:

1. A rnuffler for internal combustion engines comprising a substantiallyhorizontal inlet conduit open at one end and closed at the opposite endinto which exhaust gases enter at the open end of said inlet conduit andpass into said conduit toward the closed end thereof, said conduittapering from a relatively large open end to a relatively small closedend; and a substantially horizontal outlet conduit arranged below andparallel to the inlet conduit and also open at the outlet end and closedat the opposite end, said open end being at the opposite end of thedevice from the open end of the inlet conduit and tapering from arelatively large open end to a relatively small closed end; and aplurality of sloping connecting conduits interconnecting said inlet andoutlet conduits, through which exhaust gases flow from said inletconduit to said outlet conduit and then toward and out of the open endof said outlet conduit wherein a plurality of the interconnectingconduits slope downwardly and rearwardly from the closed end of theinlet conduit toward the closed end of the outlet conduit whereby thegreater portion of said exhaust gases follow an S path through saidmufiler wherein a plurality of the interconnecting conduits extendsubstantially perpendicularly between said inlet conduit and said outletconduit and wherein the sloping tubes near the inlet end of said mufilerare larger in diameter than the sloping tubes nearer to the outlet end;wherein the average crosssectional area of each one of saidinterconnecting conduits is individually less than the averagecross-sectional area of said inlet conduit; wherein the totalcross-sectional area of all of the interconnecting conduits is at leastas great as the greatest cross-sectional area of said inlet conduit andat least as great as the greatest crosssectional area of the outletconduit; and said device being formed of two complementary stampedplates secured to each other.

2. A mufiler for internal combustion engines comprising an inlet conduitopen at one end and closed at the opposite end into which exhaust gasesenter at the open end of said inlet conduit and pass into said conduittoward the closed end thereof; an outlet conduit arranged parallel tothe inlet conduit and below the inlet conduit and open at its outlet endand closed at the opposite end through which exhaust gases pass forwardand then out of the open end and of which the open end of said outletconduit is at the opposite end of the device from the open end of theinlet conduit; a plurality of sloping connecting conduitsinterconnecting said inlet and outlet conduits through which exhaustgases flow from said inlet conduit to said outlet and then toward andout of the open end of said outlet conduit wherein the interconnectingconduits slope from the closed end of the inlet conduit toward theclosed end of the outlet conduit at an acute angle to the inlet andoutlet conduits, whereby the greater portion of said exhaust gasesfollow an S path through said mufiler; and a drain conduit extendingsubstantially perpendicularly between the said inlet conduit and saidoutlet conduit.

References Cited in the file of this patent UNITED STATES PATENTS1,708,002 Warhus Apr. 9, 1929 1,990,002 Morgenstern Feb. 12, 19352,118,056 Peik May 24, 1938 2,484,826 Harley Oct. 18, 1949 FOREIGNPATENTS 724,862 France Feb. 5, 1932 763,327 Great Britain Dec. 12, 1956,

. UNITED STATES PATENT orrmr QERTWEQATE 'F Patent Non 2 96e 955 January3 1961 Roy Ba Smih at 31.0

It is hereby certified that error appears in "the above numbered perentrequiring correction and that the said Letters Patent should read ascorrected below,

Column 3 line 49 for muffler to read muffler of Signed and eealed this5th day of Sepfiember 1961o (SEAL) Attest:

ERNEST W. SWIDER DAVID L LADD Commissioner of Patents Attesting OfficerUSCOM M-DC Patent No, 23669955 I Roy 13., Smieh e1; e10

ror appears in the above nmnbered pat- It is hereby certified that er 5Patent should read as ent requiring correction and-that the said Lettercorrected below Column. 3 line 4L9 for "muffler to reed muffler ofSigned and sealed this 5th; day of September 1961,

(SEAL) Attest:

DAVID L. LADD ERNEST W. SWIDER Attesting Officer Commissioner of PatentsV U$COMM-DC

